U.S. patent application number 16/707448 was filed with the patent office on 2020-04-09 for photosensitive material and method of lithography.
The applicant listed for this patent is Taiwan Semiconductor Manufacturing Co., Ltd.. Invention is credited to Ching-Yu Chang, Chien-Wei Wang, An-Ren Zi.
Application Number | 20200110338 16/707448 |
Document ID | / |
Family ID | 59019939 |
Filed Date | 2020-04-09 |
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United States Patent
Application |
20200110338 |
Kind Code |
A1 |
Zi; An-Ren ; et al. |
April 9, 2020 |
Photosensitive Material and Method of Lithography
Abstract
Materials directed to a photosensitive material and a method of
performing a lithography process using the photosensitive material
are described. A semiconductor substrate is provided. A first layer
including a floating additive is formed over the semiconductor
substrate. A second layer including an additive component having a
metal cation is formed over the first layer. One or more bonds are
formed to bond the metal cation and one or more anions. Each of the
one or more anions is one of a protecting group and a polymer chain
bonding component. The polymer chain bonding component is bonded to
a polymer chain of the layer. The second layer is exposed to a
radiation beam.
Inventors: |
Zi; An-Ren; (Hsinchu City,
TW) ; Chang; Ching-Yu; (Yilang County, TW) ;
Wang; Chien-Wei; (Hsinchu County, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Taiwan Semiconductor Manufacturing Co., Ltd. |
Hsin-Chu |
|
TW |
|
|
Family ID: |
59019939 |
Appl. No.: |
16/707448 |
Filed: |
December 9, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15150171 |
May 9, 2016 |
10503070 |
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16707448 |
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62265869 |
Dec 10, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03F 7/091 20130101;
G03F 7/32 20130101; H01L 21/0271 20130101; H01L 21/0274 20130101;
G03F 7/11 20130101; G03F 7/0042 20130101; G03F 7/168 20130101; G03F
7/16 20130101; G03F 7/20 20130101 |
International
Class: |
G03F 7/20 20060101
G03F007/20; H01L 21/027 20060101 H01L021/027; G03F 7/32 20060101
G03F007/32; G03F 7/16 20060101 G03F007/16; G03F 7/09 20060101
G03F007/09; G03F 7/004 20060101 G03F007/004; G03F 7/11 20060101
G03F007/11 |
Claims
1. A method of semiconductor device fabrication, wherein the method
comprises: forming a first additive layer on a target substrate,
wherein the first additive layer includes an additive component
including a metal; forming a photoresist layer include an acid
generator adjacent to the first additive layer; and exposing the
target substrate having the first additive layer and the
photoresist layer disposed thereon using a radiation, wherein the
additive component of the first additive layer absorbs the
radiation and generates a secondary electron; and wherein the acid
generator of the photoresist layer generates an acid using energy
of the secondary electron.
2. The method of claim 1, wherein the forming the first additive
layer further comprises: mixing a first material and an additive
material including the additive component to form a mixture,
wherein the mixture is one of a copolymer of the first material and
the additive component and a blending polymer of the first material
and the additive component; and depositing the mixture on the
substrate to form the first additive layer.
3. The method of claim 2, wherein the mixture includes a floating
additive component, further comprising: after the depositing the
mixture, floating the floating additive material to a top region of
the first additive layer.
4. The method of claim 1, further comprising: forming a second
additive layer including the additive component on the target
substrate, wherein the photoresist layer is disposed between the
first and second additive layers.
5. The method of claim 4, wherein the photoresist layer is disposed
over the second additive layer, and wherein the second additive
layer has a concentration of the additive component greater than a
concentration of the additive component in the first additive
layer.
6. A method of making a semiconductor device, the method
comprising: providing a semiconductor substrate; forming a first
layer including a floating additive component over the
semiconductor substrate forming a second layer including a polymer
chain, a floating additive component, and a volatile additive
component over the first layer, wherein the volatile additive
component includes a metal cation, and wherein the forming the
second layer further includes: forming one or more bonds bonding
the metal cation and one or more anions, wherein each of the one or
more anions is one of a protecting group and a polymer chain
bonding component, and wherein the polymer chain bonding component
is bonded to the polymer chain of the second layer; floating the
floating additive component to a region that is adjacent to a top
surface of the second layer; and exposing the second layer to a
radiation beam.
7. The method of claim 6, wherein the one or more bonds remain
substantially the same during the exposing the second layer to the
radiation beam.
8. The method of claim 6, wherein the metal cation is a cation of a
metal selected from the group consisting of Cs, Ba, La, and Ce.
9. The method of claim 6, wherein the protecting group includes at
least four carbon atoms.
10. The method of claim 6, wherein the polymer chain bonding
component includes at least one selected from the group consisting
of a 1.about.9 carbon unit with hydrogen or halogen, --S--, --P--,
--P(O.sub.2)--, --C(.dbd.O)S--, --C(.dbd.O)O--, --O--, --N--,
--C(.dbd.O)N--, --SO.sub.2O--, --SO.sub.2S--, --SO--, --SO.sub.2--,
carboxylic acid, ether, ketone, and ester unit.
11. The method of claim 6, wherein the one or more bonds further
includes: a first bond bonding the metal cation and the protecting
group; and a second bond between the metal cation and the polymer
chain bonding component.
12. The method of claim 6, wherein the protecting group includes
the following chemical formula: ##STR00006## wherein includes a
carbon chain including a carbon number between 1 and 10, wherein R3
includes at least one selected from the group consisting of --S--,
--P--, --P(O.sub.2)--, --C(.dbd.O)S--, --C(.dbd.O)O--, --O--,
--N--, --C(.dbd.O)N--, --SO.sub.2O--, --SO.sub.2S--, --SO--, and
--SO.sub.2--, and wherein R4 includes a tertiary carbon.
13. The method of claim 12, further comprising: during the exposing
the second layer to the radiation beam, R4 of the protecting group
leaves the protecting group.
14. The method of claim 19, wherein the forming the second layer
including the volatile additive component includes performing a
doping process to form the volatile additive component.
15. A method, comprising: forming a floating additive component in
a first layer over a substrate: forming a photosensitive layer over
the first layer, wherein the photosensitive layer comprises a
polymer chain and a sensitizer additive component, wherein the
sensitizer additive component includes: a metal selected from the
group consisting of Cs, Ba, La, and Ce; and a protecting group
bonded to the metal by a first bond; a polymer chain bonding
component bonded to the metal by a second bond, the polymer chain
bonding component being further bonded to the polymer chain of the
photosensitive layer by a third bond, wherein the protecting group
includes the following chemical formula: ##STR00007## wherein
includes a carbon chain including a carbon number between 1 and 10,
the being bonded to the metal by the first bond, wherein R3
includes a material selected from the group consisting of --S--,
--P--, --P(O.sub.2)--, --C(.dbd.O)S--, --C(.dbd.O)O--, --O--,
--N--, --C(.dbd.O)N--, --SO.sub.2O--, --SO.sub.2S--, --SO--,
--SO.sub.2--, and combinations thereof, and wherein R4 includes a
tertiary carbon; floating the floating additive component to a
region adjacent a top surface of the photosensitive layer.
selectively exposing the photosensitive layer to a radiation beam;
and applying a developer to the photosensitive layer, wherein the
developer removes regions of the photosensitive layer exposed to
the radiation beam.
16. The method of claim 15, wherein prior to the exposure, the
sensitizer additive component in the photosensitive layer exhibits
hydrophobic properties, and wherein after the exposure, the
sensitizer additive component in the regions of the photosensitive
layer exposed to the radiation beam exhibits hydrophilic
properties.
17. The method of claim 15, further comprising: during the
exposure, R3 of the protecting group reacts with H.sup.+ provided
by an acid generator of the photosensitive layer.
18. The method of claim 17, further comprising: during the
exposure, R4 of the protecting group leaves the protecting
group.
19. The method of claim 15, further comprising: depositing a
topcoat layer over the photosensitive layer.
20. The method of claim 15, wherein the forming the photosensitive
layer includes: performing a doping process to form the additive
component in the photosensitive layer.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent claims the benefit of U.S. Provisional
Application No. 62/265,869, filed Dec. 10, 2015, and is a
divisional of U.S. application Ser. No. 15/150,171 filed May 9,
2016, the entire disclosures of which are incorporated herein by
reference.
BACKGROUND
[0002] The semiconductor integrated circuit (IC) industry has
experienced rapid growth. Technological advances in IC materials
and design have produced generations of ICs where each generation
has smaller and more complex circuits than the previous generation.
However, these advances have increased the complexity of processing
and manufacturing ICs and, for these advances to be realized,
similar developments in IC processing and manufacturing are needed.
In the course of IC evolution, functional density (i.e., the number
of interconnected devices per chip area) has generally increased
while geometry size (i.e., the smallest component that can be
created using a fabrication process) has decreased.
[0003] As the semiconductor device sizes continue to shrink, for
example below 20 nanometer (nm) nodes, traditional lithography
technologies have optical restrictions, which leads to resolution
issues and may not achieve the desired lithography performance. In
comparison, extreme ultraviolet (EUV) lithography can achieve much
smaller device sizes. However, EUV lithography still has some
shortcomings related to photoresist, for example shortcomings with
respect to sensitivity and/or efficiency. As a result, lithography
performance may be compromised or degraded.
[0004] Thus, a process and material that reduces, minimizes, or
removes problems with a patterning material is desired.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Aspects of the present disclosure are best understood from
the following detailed description when read in association with
the accompanying figures. It is noted that, in accordance with the
standard practice in the industry, various features in the drawings
are not drawn to scale. In fact, the dimensions of illustrated
features may be arbitrarily increased or decreased for clarity of
discussion.
[0006] FIG. 1 is a flowchart of an embodiment of a method for
making a semiconductor device according to various aspects of the
present disclosure.
[0007] FIG. 2 is a flowchart of an embodiment of a method for
forming a patterning layer according to various aspects of the
present disclosure.
[0008] FIG. 3 is a flowchart of an embodiment of a method for
forming a patterning layer according to various aspects of the
present disclosure.
[0009] FIG. 4A is a flowchart of an embodiment of a method for
forming a patterning layer according to various aspects of the
present disclosure. FIG. 4B is a flowchart of an embodiment of a
method for forming a patterning layer according to various aspects
of the present disclosure. FIG. 4C is a flowchart of an embodiment
of a method for forming a patterning layer according to various
aspects of the present disclosure. FIG. 4D is a flowchart of an
embodiment of a method for making a semiconductor device according
to various aspects of the present disclosure.
[0010] FIGS. 5A, 5B, 6, 7, 8, and 9 are diagrammatic fragmentary
cross-sectional side views of an embodiment of a semiconductor
device according to various aspects of the present disclosure.
[0011] FIGS. 10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 10I, 10J, 10K,
11A, 11B, 11C, and 11D illustrate embodiments of an additive
component according to various aspects of the present
disclosure.
[0012] FIGS. 12A, 12B, and 12C are diagrammatic fragmentary
cross-sectional side views of an embodiment of a semiconductor
device according to various aspects of the present disclosure. FIG.
12D illustrates an embodiment of a floating additive material
according to various aspects of the present disclosure.
[0013] FIGS. 13, 14, 15A, 15B, 15C, 15D, and 16 are diagrammatic
fragmentary cross-sectional side views of an embodiment of a
semiconductor device according to various aspects of the present
disclosure.
DETAILED DESCRIPTION
[0014] The following disclosure provides many different
embodiments, or examples, for implementing different features of
the provided subject matter. Specific examples of components and
arrangements are described below to simplify the present
disclosure. These are, of course, merely examples and are not
intended to be limiting. For example, the formation of a first
feature over or on a second feature in the description that follows
may include embodiments in which the first and second features are
formed in direct contact, and may also include embodiments in which
additional features may be formed between the first and second
features, such that the first and second features may not be in
direct contact. In addition, the present disclosure may repeat
reference numerals and/or letters in the various examples. This
repetition is for the purpose of simplicity and clarity and does
not in itself dictate a relationship between the various
embodiments and/or configurations discussed.
[0015] Further, spatially relative terms, such as "beneath,"
"below," "lower," "above," "upper" and the like, may be used herein
for ease of description to describe one element or feature's
relationship to another element(s) or feature(s) as illustrated in
the figures. The spatially relative terms are intended to encompass
different orientations of the device in use or operation in
addition to the orientation depicted in the figures. The apparatus
may be otherwise oriented (rotated 90 degrees or at other
orientations) and the spatially relative descriptors used herein
may likewise be interpreted accordingly.
[0016] Extreme ultraviolet (EUV) lithography has become widely used
due to its ability to achieve small semiconductor device sizes, for
example for 20 nanometer (nm) technology nodes or smaller. The EUV
photolithography process using a EUV light with a wavelength of
about 13.5 nm. However, an acid generator in the photoresist may
not absorb such a low-wavelength UV light. According to the acid
generating mechanism of the EUV exposure, a sensitizer may be used
in the EUV lithography process. A sensitizer includes an element
that absorbs the EUV light and generates secondary electrons. When
the EUV light strikes the photoresist, the sensitizer in the
photoresist absorbs the EUV light and generates secondary
electrons. These secondary electrons then react with the acid
generator to generate acid. Thereafter, the acid reacts with the
photoresist polymers changing the chemical properties of the
photoresist polymers. However, this process may suffer from poor
acid generation sensitivity and efficiency due to weak EUV light
absorption of the main elements (e.g., carbon, oxygen, and
hydrogen) of the polymer and the acid generator in the photoresist.
The present disclosure enhances photoresist sensitivity and
efficiency while balancing sensitivity, resolution, and line width
roughness (LWR) by using a sensitizer additive material having an
element having higher EUV light absorption than the main elements
of the photoresist.
[0017] FIG. 1 is a flowchart of an embodiment of a method 100 of
making a semiconductor device 500 according to aspects of the
present disclosure. FIGS. 2, 3, 4A, 4B, 4C, and 4D are flowcharts
of various embodiments of methods of forming a patterning layer
including sensitizer additive components at block 104 of the method
100. It is understood that the method 100 includes steps having
features of a complementary metal-oxide-semiconductor (CMOS)
technology process flow and thus, are only described briefly
herein. Additional steps may be performed before, after, and/or
during the method 100.
[0018] It is also understood that parts of the semiconductor device
500 may be fabricated by complementary metal-oxide-semiconductor
(CMOS) technology process flow, and thus some processes are only
briefly described herein. Further, the semiconductor device 500 may
include various other devices and features, such as additional
transistors, bipolar junction transistors, resistors, capacitors,
diodes, fuses, etc., but is simplified for a better understanding
of the inventive concepts of the present disclosure.
[0019] The semiconductor device 500 may be an intermediate device
fabricated during processing of an integrated circuit, or portion
thereof, that may comprise static random access memory (SRAM)
and/or other logic circuits, passive components such as resistors,
capacitors, and inductors, and active components such as P-channel
field effect transistors (PFET), N-channel FET (NFET), metal-oxide
semiconductor field effect transistors (MOSFET), complementary
metal-oxide semiconductor (CMOS) transistors, bipolar transistors,
high voltage transistors, high frequency transistors, other memory
cells, and combinations thereof. The semiconductor device 500 may
include a plurality of semiconductor devices (e.g., transistors),
which may be interconnected.
[0020] The method 100 begins at block 102 providing a substrate
including a target layer. Referring to the example of FIG. 5A, a
substrate 502 is illustrated. The substrate may be a semiconductor
substrate, such as a semiconductor wafer. The substrate may include
silicon in a crystalline structure. In alternative embodiments, the
substrate may include germanium, silicon germanium, silicon
carbide, gallium arsenide, indium arsenide, indium phosphide,
and/or other suitable materials. The substrate may be a
silicon-on-insulator (SOI) substrate.
[0021] In some embodiments, the substrate 502 is substantially
conductive or semi-conductive. The electrical resistance may be
less than about 10.sup.3 ohm-meter. In some embodiments, the
substrate 502 contains metal, metal alloy, metal nitride, and/or
metal/sulfide/selenide/oxide/silicide with the formula MXa, where M
is a metal, and X is N, S, Se, O, Si, and where "a" is in a range
from about 0.4 to about 2.5. For example, the substrate 502 may
contain Ti, Al, Co, Ru, TiN, WN.sub.2, and/or TaN.
[0022] In some other embodiments, the substrate 502 contains a
dielectric material with a dielectric constant in a range from
about 1 to about 40. In some other embodiments, the substrate 502
contains Si, metal oxide, or metal nitride, where the formula is
MXb, wherein M is a metal or Si, and X is N or O, and wherein "b"
is in a range from about 0.4 to about 2.5. For example, the
substrate 502 may contain SiO.sub.2, silicon nitride, aluminum
oxide, hafnium oxide, and/or lanthanum oxide.
[0023] In some embodiments, the substrate 502 may include a
plurality of layers and/or features formed on the semiconductor
substrate including doped regions or wells, isolation regions such
as shallow trench isolation (STI) features, conductive layers,
insulating layers, and various other suitable features. For
example, the substrate may include one or more target layers, which
are desired to patterned. In embodiments, the substrate 502 has any
plurality of layers (conductive layer, insulator layer) or features
(source/drain regions, gate structures, interconnect lines and
vias), formed thereon. The substrate 502 may include one or more
target layers 504 disposed on a semiconductor substrate; the target
layers 504 suitable for patterning by the method 100, and may be
referred to as patternable layers 504. Exemplary target layers
include gate layers, interconnect layers, and/or other suitable
layers. In some embodiments, the target layer 504 includes a
dielectric material, such as silicon oxide or silicon nitride. In
some embodiments, the target layer 504 includes metal. In some
embodiments, the target layer 504 includes a semiconductor
material. It is understood that the substrate 502 and the target
layer 504 may each include additional suitable material
compositions in other embodiments.
[0024] In some embodiments, the patterning by the method 100 may be
suitable to etch portions of the semiconductor substrate 502 itself
(e.g., such as in the formation of fins for a fin-type field effect
transistor).
[0025] Referring now to FIG. 1, the method 100 then proceeds to
block 104, where a patterning layer including a sensitizer additive
component may be formed over the substrate. In various embodiments,
when the patterning layer 506 is exposed to a EUV light (e.g.,
during a subsequent EUV photolithography process using a EUV light
having a wavelength of about 13.5 nm), the sensitizer additive
component in the patterning layer 506 may absorb the EUV light and
release secondary electrons, which then react with the PAG to
generate acid. As such, the sensitizer additive component may be
used to improve sensitivity of the patterning layer 506. The
sensitizer additive component is discussed in detail below with
reference to FIGS. 2 and 10A-11D.
[0026] Referring to the example of FIG. 5A, a patterning layer 506
is disposed over the target layer 504. In some embodiments, the
patterning layer 506 may include one or more layers have different
optical properties. For example, the patterning layer 506 may
include a tri-layer stack including a bottom inorganic layer (also
referred to as an underlayer tri-layer stack), a middle
anti-reflective coating layer (also referred to as a middle layer
of the tri-layer stack), and a top photoresist layer (also referred
to as a photoresist layer of the tri-layer stack). In some
examples, the various layers of the patterning layer 506 may
comprise substantially different refractive indexes (i.e., n
values), extinction coefficients (i.e., k values), or thicknesses
(T). In some embodiments, the various layers of the patterning
layer 506 may further comprise different etching resistances and
may contain at least one etching resistant molecule. The etching
resistant molecule may include a low onishi number structure,
double bond, triple bond, silicon, silicon nitride, Ti, TiN, Al,
aluminum oxide, SiON, or combinations thereof.
[0027] In the illustrated example of FIG. 5A, the patterning layer
506 includes a positive photoresist, but it is understood that the
patterning layer 506 may include a negative photoresist in
alternative embodiments. The patterning layer 506 may contain
components such as a polymer, photoacid generators (PAG), thermal
acid generators (TAG), quenchers, chromophore, surfactant, cross
linker, etc. In an embodiment, the PAG is bonded to the polymer. In
some embodiments, in a subsequent photolithography process, photons
induce decomposition of the PAG. As a result, a small amount of
acid is formed, which further induces a cascade of chemical
transformations in the patterning layer 506. The patterning layer
506 may also optionally include a quencher that is disposed within
the patterning layer 506 in order to improve critical dimension
(CD) control.
[0028] Referring now to FIG. 5B, in some embodiments, at block 104,
a topcoat layer 508 may be formed over the patterning layer 506. In
some embodiments, the sensitizer additive component in the
patterning layer 506 may be volatile and diffuse out of the
patterning layer 506. The topcoat layer 508 may act as a diffusion
barrier layer so that the sensitizer additive component remains in
the patterning layer 506. In some embodiments, the topcoat layer
508 may include a top antireflective coating (TARC), and/or other
organic or inorganic coatings as known in the art. The topcoat
layer 508 may be formed by a spin-on coating process, chemical
vapor deposition process (CVD), physical vapor deposition (PVD)
process, and/or other suitable deposition processes.
[0029] Referring now to FIG. 1, the method 100 then proceeds to
block 106, where an exposure process is performed to expose the
patterning layer thereby patterning the patterning layer. As
discussed in detail below, the sensitizer additive components
contained in the patterning layer 506 may promote more efficient
photo-acid generation, thereby enhancing photoresist sensitivity
and efficiency while balancing sensitivity, resolution, and line
width roughness (LWR). The radiation beam may expose the resist
deposited on the substrate using a lithography system that provides
a pattern of the radiation according to an IC design layout. In one
embodiment, a lithography system includes an ultraviolet (UV)
radiation, a deep ultraviolet (DUV) radiation, an extreme
ultraviolet (EUV) radiation, an X-ray radiation, and/or other
suitable radiation types. In alternative embodiments, a lithography
system includes a charged particle lithography system, such as an
electron beam or an ion beam lithography system.
[0030] Referring now to the example of FIG. 6, a patterned
radiation beam 602 is incident on the substrate 502 and
specifically the patterning layer 506. The regions 506A illustrate
the portions of the resist that have been exposed to the radiation,
and thus, a chemical change has occurred in those regions. In the
illustrated example of FIG. 6, the patterning layer 506 includes
positive resist, and the regions 506A become soluble in developers.
Alternatively, in the case of negative resist, the regions 506A are
insoluble in developers.
[0031] In embodiments of the method 100, after the exposure
process, a baking process may occur. The bake may be a hard bake.
In an embodiment, the patterning layer 506 may include a chemically
amplified resist (CAR), and the bake process serves to improve the
insolubility of the CAR.
[0032] The method 100 then proceeds to block 108 where the exposed
layer(s) are developed to form a masking element. A developer may
be applied to the exposed resist to form a resist pattern on the
substrate. In an embodiment, a positive tone developer is applied
in block 108. The term "positive tone developer" refers to a
developer that selectively dissolves and removes areas that
received exposure dose (or an exposure dose above a predetermined
threshold exposure dose value). In an embodiment, a negative tone
developer is applied in block 108. The term "negative tone
developer" refers to a developer that selectively dissolves and
removes areas that received no exposure dose (or an exposure dose
below a predetermined threshold exposure dose value).
[0033] In an embodiment, a developer may include an organic solvent
or a mixture of organic solvents, such as methyl a-amyl ketone
(MAK) or a mixture involving the MAK. In another embodiment, a
developer includes a water based developer, such as
tetramethylammonium hydroxide (TMAH). Applying a developer includes
spraying a developer on the exposed patterning layer 506, for
example by a spin-on process. In an embodiment, the developer may
remove the exposed regions 506A of the patterning layer 506.
[0034] Referring to the example of FIG. 7, a masking element 702 is
provided in the patterning layer 506. The masking element 702 may
be formed by applying a developer to the exposed patterning layer
506. In an embodiment, the masking element 702 is used to etch an
underlying layer. In turn, the etched underlying layer may be used
as a masking element to pattern additional layers. In other
embodiments or further embodiments, one or more of the layers on
the substrate 502 may also be patterned using subsequent etching
processes such as dry etching or plasma etching based on the
pattern provided by the masking elements 702.
[0035] Referring now to FIGS. 1 and 8, the method 100 then proceeds
to block 110, where the masking element is used to form a
semiconductor device feature. In an embodiment, the masking element
includes one or more of layers (e.g., the photoresist layer, the
middle layer, and/or the underlayer) of the patterning layer 506.
In a further embodiment, a photoresist layer of the patterning
layer 506 is stripped after transferring the pattern to a middle
layer (by suitable etching process discussed above) of the
patterning layer 506. The patterned middle layer may then be used
as the masking element to pattern additional layer(s). Referring to
the example of FIG. 8, features 802 are formed of the target layer
504 of the substrate 502. The features 802 are defined by the
masking element 702. Features 802 may be gate structures, fin
structures such as provided in a fin-type field effect transistor,
interconnect structures, isolation features, conductive features
such as lines, and/or other suitable semiconductor device
features.
[0036] The method 100 may continue with further steps not
specifically described herein but understood by one of ordinary
skill in the art. For example, the semiconductor device 500 may
next be subjected to a rinsing process, such as a de-ionized (DI)
water rinse. The rinsing process may remove residue particles.
[0037] Referring now to FIGS. 2, 9, 10A, 10B, 10C, 10D, 10E, 11A,
11B, 11C, and 11D, illustrated is an exemplary embodiment of a
method 200 of forming a patterning layer including a sensitizer
additive component at block 104 of the method 100. In some
embodiments, the patterning layer may be a tri-layer patterning
layer including an underlayer, a middle layer disposed over the
underlayer, and a photoresist layer disposed over the middle layer.
In some embodiments, one or more of the underlayer, middle layer,
and photoresist layer may include sensitizer additive components,
which may improve the sensitivity of the patterning layer.
[0038] Referring to FIG. 2 and the example of FIG. 9, the method
200 begins at block 202, where an underlayer 902 of the patterning
layer 506 is formed on the substrate 502. The underlayer may be a
first (e.g., nearest the substrate) layer of the tri-layer
patterning layer 506 and include a sensitizer additive component
910. In an embodiment, an underlayer material of the underlayer 902
includes an organic material. In a further embodiment, the organic
material includes a plurality of monomers or polymers that are not
cross-linked. In some embodiments, the underlayer material may
contain a material that is patternable and/or have a composition
tuned to provide anti-reflection properties. In some embodiments,
the underlayer material includes a solvent. For example, the
solvent may include an organic solvent may including dimethyl
sulfoxide (DMSO), tetrahydrofuran (THF), propylene glycol methyl
ether (PGME), propylene glycol methyl ether acetate (PGMEA),
n-Butyl acetate, Cyclohexanol, .gamma.-Butyrolactone (GBL),
ethanol, propanol, butynol, methanol, ethylene, glycol,
gamabutylactone, N-Methyl-2-pyrrolidone (NMP), alkylsulfoxide,
carboxylic ester, carboxylic acid, alcohol, glycol, aldehyde,
ketone, acid anhydride, lactone, halogenated alkane,
non-halogenated alkane, branched alkane, non-branched alkane,
cyclic alkane, non-cyclic alkane, saturated alkane, non-saturated
alkane, or a combination thereof.
[0039] In some embodiments, the sensitizer additive component 910
includes a metal that absorbs the radiation (e.g., the EUV light)
in a EUV exposure to generate secondary electrons. In some
embodiments, the metal may have an absorption coefficient of the
EUV light greater than an absorption coefficient for the main
elements (e.g., carbon, oxygen, and hydrogen) of the polymer and
the acid generator in the underlayer and/or or other layers of the
patterning layer 506. For example, the metal may include one of Te,
Pb, Sn, Ag, Bi, Sb, Cs, Ba, La, Ce, and In. For further example,
the metal may be a metal cation including one of Cs.sup.n1+,
Ba.sup.n2+, La.sup.n3+, Ce.sup.n4+, where n1 is equal to or greater
than 1, and each of the n2, n3, and n4 may be equal to or greater
than 2. In some examples, the metal may be a metal cation including
one of In.sup.n+ and Ag.sup.n+, where n is an integer equal to or
greater than 1. In some examples, the metal may be a metal cation
including Sn.sup.2+, Sn.sup.4+, or a Sn cation having a charge
magnitude that is greater than 4.
[0040] In some embodiments, the sensitizer additive component 910
may include one or more anions, and bonds (e.g., ionic bond) are
formed between the metal cation and each of the one or more anions.
In some embodiments, each of the bonds may have a bonding energy
large enough so that the bonds of the sensitizer additive component
910 are stable and do not break during a subsequent exposure
process, and the sensitizer additive component 910 remains
substantially the same during the exposure process. In some
examples, the anions include one or more of SO.sub.3--, N--, COO--,
CO.sub.3--. In some examples, the bonding energy of each of the
bonds may be equal to or greater than about 100 kcal/mol. In some
examples, the bonding energy of each of the bonds may be equal to
or greater than about 150 kcal/mol.
[0041] Referring now to the examples of FIGS. 10A, 10B, 10C, 10D,
10E, 10F, 10G, 10H, and 10I, in some embodiments, the sensitizer
additive component 910 is an isolated molecule that is not attached
to a polymer chain. In some embodiments, the total molecular weight
of the sensitizer additive component 910 may be equal to or less
than 1000. Referring to the example of FIG. 10A, a sensitizer
additive component 910 may include a metal cation 1002 bonded to
one or more anions 1004 by bonds 1006. In the example of FIG. 10A,
each anion 1004 is a protecting group which may protect the metal
cation 1002 from undesired reactions.
[0042] In some embodiments, the sensitizer additive component 910
is soluble in a particular solvent (e.g., the solvent of the
underlayer 902 and/or other layers of the patterning layer 506). In
some embodiments, as the solubility of the sensitizer additive
component 910 is a function of the anion 1004, the solubility of
the sensitizer additive component 910 may be optimized by
determining the anion 1004 based on the anion 1004's solubility in
the solvent. In some examples, the anion 1004 may have a carbon
number that is equal to or greater than four to achieve the desired
solubility in the solvent. In some embodiments, the sensitizer
additive component 910 is a single organometallic sensitizer.
[0043] In some embodiments, the bond 1006 between the metal cation
1002 and the anion 1004 of the sensitizer additive component 910
remains substantially the same during the exposure process. For
example, the bond 1006 between the metal cation 1002 and the anion
1004 has a bonding energy large enough so that the bond 1006 may
remain stable and do not break during the exposure process. In some
examples, the bonding energy may be equal to or greater than about
100 kcal/mol. In some embodiments, the total molecular weight of
the sensitizer additive component 910 may be equal to or less than
1000.
[0044] Referring now to FIGS. 10B, 10C, 10D, and 10E, in some
embodiments, the protecting groups 1004 remain substantially the
same during the exposure process. The plurality of chemical
formulas below (also shown in FIGS. 10B, 10C, 10D, and 10E)
represent some exemplary embodiments of the sensitizer additive
component 910, where the sensitizer additive component 910 is an
isolated molecule not attached to a polymer chain, and the
protecting groups 1004 of the sensitizer additive component 910
remain substantially the same during the exposure process.
##STR00001##
[0045] Referring now to the examples of FIGS. 10F, 10G, 10H, and
10I, in some embodiments, the protecting groups 1004 of the
sensitizer additive component 910 have a polarity switch function,
and may be referred to as the polarity switch protecting groups
1004 below. In some examples, the sensitizer additive component 910
including the polarity switch protecting groups 1004 may exhibit
hydrophobic properties prior to exposure. Referring to the example
of FIG. 10F, in some embodiments, the polarity switch protecting
groups 1004 includes a carbon chain 1008 (also referred to as a
spacer 1008) attaching the metal cation 1002 to a R3 unit and a R4
unit. In some examples, the number of carbons in the carbon chain
1008 may be between 1 and 10. In some examples, the number of
carbons in the carbon chain 1008 may be greater than 10. In some
examples, the carbon chain 1008 may include --CH2CH2CH2--,
--CH2CH2COCH2--, --CH2CH2CH2CH2CH2--, --CH2COCH2--, and/or other
suitable components. In some embodiments, the R3 unit may include
one or more of --S--, --P--, --P(O.sub.2)--, --C(.dbd.O)S--,
--C(.dbd.O)O--, --O--, --N--, --C(.dbd.O)N--, --SO.sub.2O--,
--SO.sub.2O--, --SO.sub.2S--, --SO--, --SO.sub.2--, and/or other
suitable components. In some embodiments, the R4 unit may include a
tertiary carbon. For example, the R4 unit may include one or more
acid labile groups (ALGs). The chemical formulas below represent
some exemplary embodiments of the R4 unit.
##STR00002##
[0046] Referring now to FIG. 10G, illustrated is an example of the
sensitizer additive component 910 where the R3 unit is
--C(.dbd.O)O--. The plurality of chemical formulas below (also
shown in FIGS. 10H and 10I) represent some exemplary embodiments of
the sensitizer additive component 910 including polarity switch
protecting groups 1004.
##STR00003##
[0047] Referring now to the examples of FIGS. 10J and 10K, in some
embodiments, during or after exposure to radiation, the R3 unit of
the polarity switch protecting group 1004 may react with H.sup.+
(e.g., provided by PAG and/or TAG), and the R4 unit may leave the
sensitizer additive component 910. The resulting sensitizer
additive component is referred to as the sensitizer additive
component 910A. In some embodiments, the sensitizer additive
component 910A may exhibit hydrophobic properties. As such, the
reaction between the R3 unit and the H.sup.30 and the leaving of
the R4 unit may make the material including the sensitizer additive
component 910A more hydrophilic in the regions exposed to radiation
(e.g., regions of 506A of FIG. 6) than those regions of
non-exposure. In some embodiments, the sensitizer additive
component 910 in those regions of non-exposure remains
substantially the same during the exposure process. Referring now
to the example of FIG. 10J, illustrated is an examples of the
sensitizer additive components 910A including the polarity switch
protecting groups 1004A bonded to the metal cation 1002 using the
bond 1006. Referring now to the example of FIG. 10K, illustrated is
an example of the resulting sensitizer additive component 910A
after the sensitizer additive components 910 of FIG. 10G is exposed
to radiation, where the R3 unit including --C(.dbd.O)O-- has
reacted with H.sup.+ to form --C(.dbd.O)OH. As such, in some
embodiments, the hydrophilic nature of the exposed regions (e.g.,
regions of 506A of FIG. 6) including the sensitizer additive
component 910A is increased, which may the contrast between exposed
and non-exposed regions and allow for optical contrast improvement.
In some embodiments, the sensitizer additive component 910A may
help increase the exposed regions' dissolution rate in a developer
used in the developing process.
[0048] Referring now to the examples of FIGS. 11A, 11B, 11C, and
11D, in some embodiments, the sensitizer additive component 910 may
be bonded to a polymer chain. Illustrated in FIG. 11A is an
exemplary copolymer 1100 including a polymer chain 1102 and a
sensitizer additive component 910 attached to the polymer chain
1102. The polymer chain 1102 may be PHS (such as PHS polymers by
DuPont.TM.), acrylate, a 1-10 carbon unit, and/or other suitable
polymer chain.
[0049] In the example of FIG. 11A, a metal cation 1002 of the
sensitizer additive component 910 may be bonded to an anion 1104
using a bond 1108 where the anion 1104 is an R1 unit (also referred
to as a polymer chain bonding component) attaching to the polymer
chain 1102. The R1 unit may be unbranched or branched, cyclic or
noncyclic, and may include saturated 1.about.9 carbon unit with
hydrogen or halogen (e.g., alkyl, alkene), --S--, --P--,
--P(O.sub.2)--, --C(.dbd.O)S--, --C(.dbd.O)O--, --O--, --N--,
--C(.dbd.O)N--, --SO.sub.2O--, --SO.sub.2O--, --SO.sub.2S--,
--SO--, --SO.sub.2--, carboxylic acid, ether, ketone, ester unit
and/or other suitable components. In some embodiments, the bonding
energy of the bond 1108 is sufficiently large so that the bond 1108
is stable and does not break during the exposure process. For
example, the bonding energy of the bond 1108 is equal to or greater
than about 100 kcal/mol. Referring to the example of FIGS. 11A,
11B, and 11C, in some embodiments, the metal cation 1002 of the
sensitizer additive component 910 may be bonded to one or more
protecting groups 1004 using bonds 1006. In some examples, the bond
energy of the bond 1006 may be equal to or greater than about 100
kcal/mol so that the bond 1006 is stable and does not break during
the subsequent exposure process. Referring to the example of FIG.
11D, in some embodiments, the metal cation 1002 is not bonded to
any protecting groups.
[0050] The plurality of chemical formulas below (also shown in
FIGS. 11B, 11C, 11D) represent some exemplary embodiments of the
copolymer 1100:
##STR00004##
[0051] In some embodiments, the underlayer 902 may be formed by
depositing a mixed material formed by mixing the underlayer
material and a sensitizer additive material including the
sensitizer additive component 910. In some embodiments, the mixed
material is formed as a blending polymer (or polymer blend). The
polymer blend may be a heterogeneous or homogeneous blend. In some
embodiments, the mixed material is formed by copolymerization of
the components. In other words, the sensitizer additive component
is a copolymer of the underlayer material.
[0052] In an embodiment, the percentage by weight of the sensitizer
additive components to a base polymer of the underlayer material is
in a range from about 0.1% to about 10%. In an embodiment, the
percentage is about 5%. In an embodiment, the percentage of the
sensitizer additive components to the base polymer is the
percentage at deposition. The percentage of the sensitizer additive
components may provide control of acid generation and the
transmittance of the patterning layer 506.
[0053] In some embodiments, the underlayer 902 may be formed by a
spin-on coating process, chemical vapor deposition process (CVD),
physical vapor deposition (PVD) process, and/or other suitable
deposition processes. In an embodiment, the underlayer is omitted.
In an embodiment, the underlayer does not include the sensitizer
additive component 910.
[0054] The method 200 then proceeds to block 204, where a middle
layer of the patterning layer 506 is formed over the substrate
and/or the underlayer. The middle layer may be a second layer of a
tri-layer patterning layer. In some embodiments, the middle layer
may have a composition that provides an anti-reflective properties
and/or hard mask properties for the lithography process. In an
embodiment, the middle layer includes a silicon containing layer
(e.g., a silicon hard mask material). The middle layer may include
a silicon-containing inorganic polymer. In a further embodiment,
the middle layer includes a siloxane polymer (e.g., a polymer
having a backbone of O--Si--O--Si-- etc.). The silicon ratio of the
middle layer material may be controlled such as to control the etch
rate. In other embodiments the middle layer may include silicon
oxide (e.g., spin-on glass (SOG)), silicon nitride, silicon
oxynitride, polycrystalline silicon, a metal-containing organic
polymer material that contains metal such as titanium, titanium
nitride, aluminum, and/or tantalum; and/or other suitable
materials.
[0055] Referring now to the example of FIG. 9, a middle layer 904
is disposed on the underlayer 902 as one component of the tri-layer
patterning layer 506. The middle layer 904 may include a suitable
material such as a hard mask material.
[0056] In some embodiments, the middle layer 904 may be formed by
depositing a material including a mixture of the middle layer
material and a sensitizer additive material including the
sensitizer additive component 910. The mixture including the
sensitizer additive component 910 may be formed substantially
similar to the mixture of the sensitizer additive material and the
underlayer material discussed above with reference the underlayer
902 of FIG. 9.
[0057] In some embodiments, the sensitizer additive material and a
middle layer material are mixed prior to depositing on a substrate.
In an embodiment, the percentage by weight of the sensitizer
additive component to a base polymer of the middle layer material
is in a range from about 0.1% to about 10%. In an embodiment, the
percentage is about 5%. In an embodiment, the percentage of the
sensitizer additive component to the base polymer is the percentage
at deposition. The percentage of the sensitizer additive component
may provide control of acid generation and the transmittance of the
patterning layer 506. In some embodiments, the middle layer 904 may
be formed by a spin-on coating process, chemical vapor deposition
process (CVD), physical vapor deposition (PVD) process, and/or
other suitable deposition processes. In an embodiment, the middle
layer is omitted. In an embodiment, the middle layer does not
include the sensitizer additive component 910.
[0058] The method 200 then proceeds to block 206 where a
photoresist layer is formed over the middle layer. The photoresist
layer may be a third, and top, layer of a tri-layer patterning
layer. The photoresist layer may be a photosensitive layer operable
to be patterned by a radiation as known in the art. The photoresist
layer may include a photoresist (e.g., a chemical amplified (CA)
resist), which is a radiation (e.g., light) sensitive material and
may be a positive tone resist (PTD) or negative tone resist (NTD).
A positive tone resist (or simply positive resist) is a type of
photoresist in which the portion of the photoresist that is exposed
to light becomes soluble to the photoresist developer. The portion
of the photoresist that is unexposed remains insoluble to the
photoresist developer. A negative tone resist (or simply negative
resist) is a type of photoresist in which the portion of the
photoresist that is exposed to light becomes insoluble to the
photoresist developer. The unexposed portion of the photoresist is
dissolved by the photoresist developer.
[0059] Specifically, the resist may include an organic polymer
(e.g., positive tone or negative tone photoresist polymer), an
organic-based solvent, and/or other suitable components known in
the art. Other components may include a photo-acid generator (PAG)
component, a thermal acid generator (TAG) component, a quencher
component, a photo-decomposable base (PDB) component, and/or other
suitable photosensitive component depending on the resist type. In
some embodiments, when absorbing photo energy from an exposure
process, the PAG forms a small amount of acid. The resist may
include a polymer material that varies its solubility to a
developer when the polymer is reacted with this generated acid.
Examples of suitable PAGs include salts of sulfonium cations with
sulfonates, salts of iodonium cations with sulfonates,
sulfonyldiazomethane compounds, N-sulfonyloxyimide PAGs,
benzoinsulfonate PAGs, pyrogallol trisulfonate PAGs, nitrobenzyl
sulfonate PAGs, sulfone PAGs, glyoxime derivatives,
triphenylsulfonium nonaflate, and/or other suitable PAGs now known
or later developed.
[0060] Exemplary organic based solvents include but are not limited
to PGMEA (propylene glycol monomethyl ether acetate)
(2-methoxy-1-methylethylacetate), PGME (propylene glycol monomethyl
ether), GBL (gamma-butyrolacetone), cyclohexanone, n-butyl acetate,
and 2-heptanone. The organic polymer resin of the photosensitive
material may include those resists formulated for KrF, ArF,
immersion ArF, EUV, and/or e-beam lithography processes. Examples
include Novolak (a phenol formaldehyde resin), PHS
(poly(4-hydroxystyrene) derivatives), poly aliphatic resist,
phenolic derivative, and/or other suitable formulations. In some
embodiments, the organic polymer resion may include a cleavable
group (ALG) and a non-cleavage group (e.g., a lactone unit, a polar
unit).
[0061] In some embodiments, the photoresist layer 906 may include
sensitizer additive component 910, which may be substantially
similar to the sensitizer additive component 910 of the underlayer
902 discussed above. In some embodiments, the photoresist layer 906
may be formed by depositing a material including a mixture of the
photoresist layer material and a sensitizer additive material
including the sensitizer additive component 910. The mixture of the
photoresist layer material and the sensitizer additive material may
be formed substantially similar to the mixture of the sensitizer
additive material and the underlayer material discussed above with
reference the underlayer 902 of FIG. 9.
[0062] In an embodiment, the percentage by weight of the sensitizer
additive component to a base polymer of the photoresist material is
in a range from about 0.1% to about 10%. In an embodiment, the
percentage of the sensitizer additive component to the base polymer
is the percentage at deposition. The percentage of the sensitizer
additive component may provide control of acid generation and the
transmittance of the patterning layer 506. For example, excessive
sensitizer additive component 910 may lower the transmittance of
the photoresist layer 906, thereby affecting its performance. In an
embodiment, the percentage by weight of the sensitizer additive
component to a base polymer of the photoresist material may be in a
range from about 0.1% to about 3%.
[0063] In some embodiments, the concentration of the sensitizer
additive component 910 in the photoresist layer 906 may have
substantially greater effect on the transmittance of the
photoresist layer 906 than the concentration of the sensitizer
additive component 910 in other layers (e.g., the underlayer 902,
the middle layer 904) of the patterning layer 506. As such, in some
embodiments, the sensitizer additive amount in the photoresist
layer 906 is lower than the sensitizer additive component amount in
the other layers. In some examples, the percentage by weight of the
sensitizer additive component 910 in the photoresist layer 906 is
less than the percentage by weight of the sensitizer additive
component 910 in the underlayer 902 or in the middle layer 904
(e.g., by at least about 50% by weight).
[0064] In some embodiments, the photoresist layer 906 may be formed
by a spin-on coating process, chemical vapor deposition process
(CVD), physical vapor deposition (PVD) process, and/or other
suitable deposition processes. In an embodiment, the photoresist
layer 906 does not include the sensitizer additive component
910.
[0065] While in the illustrated example of FIG. 9 each layer of the
patterning layer 506 includes the sensitizer additive component
910, it is understood that in various embodiments, one or more
layers of the patterning layer 506 may not include the sensitizer
additive component 910. In some examples, the photoresist layer 906
does not include the sensitizer additive component 910, while one
or both of the underlayer 902 and the middle layer 904 may include
the sensitizer additive component 910. In some examples, the
photoresist layer 906 may include the sensitizer additive component
910, while one or both of the underlayer 902 and the middle layer
904 do not include the sensitizer additive component 910. In
various embodiments, the concentration of the sensitizer additive
component 910 may be designed based on the various properties and
concentrations of the TAG, PAG, and/or quencher in one or more of
the layers of the patterning layer 506 to reach a balance
performance between sensitivity and LWR. In various embodiments,
the underlayer 902, the middle layer 904, and the photoresist layer
906 may have various sensitizer additive component concentration
profiles. In some embodiments, the sensitizer additive component
910 may be substantially uniformly distributed in the underlayer
902, the middle layer 904, and/or the photoresist layer 906. In
some embodiments, the underlayer 902, the middle layer 904, and the
photoresist layer 906 may have different sensitizer additive
component concentration profiles. In one example, the sensitizer
additive component 910 is uniformly distributed in the underlayer
902 and/or the middle layer 904, while the photoresist layer 906
may have a non-uniform sensitizer additive material concentration
profile (e.g., varied continuously or varied stepwise). In some
examples, the concentration of the sensitizer additive component
may increase with a gradient from a top surface of the photoresist
layer 906 to a bottom surface of the photoresist layer 906.
[0066] Referring now to the examples of FIGS. 12A, 12B, 12C, and
12D, in some embodiments, one or more of the underlayer 902, the
middle layer 904, and the photoresist layer 906 may include a
floating additive material. In some embodiments, the floating
additive material may include a floating unit. In some embodiments,
after deposition, the sensitizer additive component 910 in the
deposited layer may be volatile and diffuse out of the deposited
layer. A floating additive layer formed by the floating additive
material may act as a diffusion barrier layer so that the
sensitizer additive component 910 remains in the deposited layer.
For example, after deposition, the floating additive material may
form an upper layer or region at the top of the deposited layer. In
an embodiment, the properties of the floating additive material
allow the layer or region provided to be disposed at and/or move
such that a layer of the floating additive material is formed at
the top of the deposited layer. In other words, the properties of
the polymer of the floating additive material allow it to "float"
to the top of the deposited layer. The floating may be provided by
a floatable component or unit attached to a polymer chain of the
floating additive material. In some embodiments, the floating
additive material may also provide one of an acid generator
component or a base generator component, for example, also attached
to the polymer chain. The acid generator component or base
generator component can generate an acid or a base after exposure
to a radiation and/or thermal treatment. In one example, the acid
generator component may generate acid by reacting with the
secondary electrons generated by the sensitizer additive component
910 in various layers (e.g., one or more of the underlayer 902, the
middle layer 904, the photoresist layer 906) of the patterning
layer 506.
[0067] Referring now to FIGS. 12A, 12B, and 12C, illustrated is an
exemplary patterning layer 506 including a floating additive
material. Referring to the example of FIG. 12A, the underlayer 902
is formed by depositing a material including an underlayer
material, a sensitizer additive material, and a floating additive
material on the substrate. After the deposition, the floating
additive material 1202 in the underlayer 902 may form a floating
additive layer 1204 at the top of the underlayer 902, thereby
preventing the volatile sensitizer additive component 910 from
diffusing out of the underlayer 902. Referring to the example of
FIG. 12B, a middle layer 904 is disposed over the underlayer 902
and the floating additive layer 1204. In the example illustrated in
FIG. 12B, the floating additive layer 1204 may move to the top of
the middle layer 904. Alternatively, in some embodiments, the
floating additive layer 1204 may not move to the top of the middle
layer 904 and remain disposed between the underlayer 902 and the
middle layer 904. In an example, the floating additive layer 1204
disposed between the underlayer 902 and the middle layer 904 may
act as a barrier layer so that the sensitizer additive component
910 remains in the underlayer 902, which may help control the
concentrations of the sensitizer additive component 910 in the
various layers of the patterning layer 506. Referring now to the
example of FIG. 12C, a photoresist layer 906 is formed over the
middle layer 904 and the floating additive layer 1204. In the
example illustrated in FIG. 12C, after the photoresist layer 906 is
deposited, the floating additive layer 1204 may move to the top of
the photoresist layer 906. Alternatively, in some embodiments, the
floating additive layer 1204 may not move to the top of the
photoresist layer 906, and remain disposed between the middle layer
904 and the photoresist layer 906.
[0068] In various embodiments, one or more of the middle layer 904
and the photoresist layer 906 may include both the sensitizer
additive component 910 and a floating additive material 1202. In
some embodiments, after the middle layer 904 including a floating
additive material 1202 is deposited, the floating additive material
1202 may form a floating additive layer 1204 at the top of the
middle layer 904, thereby preventing the volatile sensitizer
additive component 910 in the middle layer 904 from diffusing out
of the middle layer 904. In some embodiments, after the photoresist
layer 906 is deposited, the floating additive layer 1204 moves to
the top of the photoresist layer 906. Alternatively, the floating
additive layer 1204 may remain disposed between the middle layer
904 and the photoresist layer 906 and act as a barrier so that the
sensitizer additive component 910 remains in the middle layer 904
and does not diffuse into the photoresist layer 906, which may help
control the concentrations of the sensitizer 910 in the middle
layer 904 and the overlying photoresist layer 906.
[0069] In some embodiments, after the photoresist layer 906
including a floating additive material 1202 is deposited, the
floating additive material 1202 may form a floating additive layer
1204 at the top of the photoresist layer 906, thereby preventing
the volatile sensitizer additive component 910 in the photoresist
layer 906 from diffusing out of the photoresist layer 906.
[0070] The floating additive material is now described in further
detail. The floating additive material may include a polymer having
a floatable unit. In some embodiments, the floating additive
material may include one of an acid or a base component. The
floatable unit and acid/base component may be bonded together by a
polymer backbone. Illustrated in FIG. 12D is an example of a
floatable unit 1208 attached to the polymer 1206 illustrated as a
floating additive material 1202. The polymer chain 1206 may be PHS
(such as PHS polymers by DuPont.TM.) acrylate, a 1-10 carbon unit,
and/or other suitable polymer chain. A CxFy unit is bonded to the
polymer chain 402. The CxFy may provide the "floating" properties
of the additive material, such as the additive material 400 of FIG.
4 of the additive material 500 of FIG. 5. The CxFy component may be
a chain or branched unit. The number of carbons (x) may be between
one (1) and nine (9), including 1 and 9. The number of florines (y)
may be greater than 0 (e.g., between one (1) and nine (9),
including 1 and 9).
[0071] In some embodiments, a R2 component may connect the CxFy
unit to the polymer chain 1206. In other embodiments, the R2
component is omitted and the CxFy unit is connected directly to the
polymer chain 1206. The R2 unit may be unbranched or branched,
cyclic or noncyclic, and may include saturated 1.about.9 carbon
unit with hydrogen or halogen (e.g., alkyl, alkene), or --S--,
--P--, --P(O.sub.2)--, --C(.dbd.O)S--, --C(.dbd.O)O--, --O--,
--N--, --C(.dbd.O)N--, --SO.sub.2O--, --SO.sub.2O--, --SO.sub.2S--,
--SO--, --SO.sub.2--, carboxylic acid, ether, ketone, ester unit
and/or other suitable components.
[0072] Exemplary floating unit 1202 components may include one of
the following:
##STR00005##
[0073] Referring now to FIGS. 3, 13, and 14, illustrated is another
exemplary embodiment of a method 300 of forming a patterning layer
including a sensitizer additive component at block 104 of the
method 100. In such embodiments of the method 300, the sensitizer
additive component in the patterning layer is formed using a doping
process.
[0074] Referring to FIG. 3 and the example of FIG. 13, the method
300 starts at block 302, where an underlayer 902 is formed over the
substrate 502. Block 302 may be substantially similar to block 202.
In the example illustrated in FIG. 13, the underlayer 902 does not
include the sensitizer additive component at this stage of the
process. The method 300 proceeds to block 304, where a middle layer
904 is formed over the underlayer. Block 304 may be substantially
similar to block 204. In the example illustrated in FIG. 13, the
middle layer 904 does not include the sensitizer additive component
at this stage of the process. The method 300 then proceeds to block
306, where a photoresist layer is formed over the middle layer 904.
Block 306 may be substantially similar to block 306. In the example
illustrated in FIG. 13, the middle layer 906 does not include the
sensitizer additive component at this stage of the process.
[0075] In some embodiments, one or more of the underlayer 902,
middle layer 904, and photoresist layer may include a floating
additive material 1202, thereby forming one or more floating
additive layers 1204. In the example of FIG. 13, a first floating
additive layer 1204 is disposed over the photoresist layer 906, and
a second floating additive layer 1204 is disposed between the
middle layer 904 and the photoresist layer 906. However, it is
understood that various configurations of the floating additive
layers 1204 in the patterning layer 506 may be used to reduce the
diffusion of the sensitizer additive and control the concentration
and distribution of the sensitizer additive component in the
various layers of the patterning layer 506. In some examples, a
floating additive layers 1204 may be disposed between the
underlayer 902 and the middle layer 904. In some examples, there is
no floating additive layer 1204 disposed over the photoresist layer
906.
[0076] The method 300 then proceeds to block 308, where a doping
process is performed to the patterning layer 506, so that the
sensitizer additive component 910 is formed in one or more of the
underlayer, the middle layer, and the photoresist layer. Referring
now to FIG. 13, a doping process 1302 is performed to the
patterning layer 506 of a device 1300. In some embodiments, the
doping process 1302 includes an ion implantation process implanting
ions into one or more of the underlayer, the middle layer, and the
photoresist layer. In some embodiments, the dopant may include at
least one of Te, Pb, Sn, Ag, Bi, Sb, Cs, Ba, La, Ce, and Ln. For
further example, the dopant may include Cs.sup.n1+, Ba.sup.n2+,
La.sup.n3+, and/or Ce.sup.n4+, where n1 is equal to or greater than
1, and each of n2, n3, and n4 is equal to or greater than 2. In
some examples, the dopant may include a metal cation including one
of In.sup.n+ and Ag.sup.n+, where n is an integer equal to or
greater than 1. In some examples, the dopant may include Sn.sup.2+,
Sn.sup.4+, and/or a Sn metal cation having an order higher than
4.
[0077] In some embodiments, the dopant may include one or more of
the protective groups 1004. In some embodiments, the implanted ions
may attach to each other or components in the underlayer, middle
layer, or photoresist layer to form the sensitizer additive
component 910. In some embodiments, the resulting sensitizer
additive component 910 in one or more of the underlayer, the middle
layer, and the photoresist layer may be substantially similar to
the sensitizer additive component 910 discussed above with
references to FIGS. 10A-11D.
[0078] In various embodiments, the sensitizer additive component
concentration (e.g., by controlling dopant species, ion beam
energy, implantation dose, implantation depth of the ion
implantation process 1302) so as to result in desired concentration
and concentration profile of the sensitizer additive component. In
some embodiments, the ion implantation process includes multiple
implantation steps to achieve the desired sensitizer additive
component concentration.
[0079] Referring now to the example of FIG. 14, illustrated is the
device 1300 after the doping process is performed. In some
embodiments, the various layers of the patterning layer 506 may
have different sensitizer additive component concentration. In some
examples, the photoresist layer 906 may have a sensitizer additive
component concentration less than the sensitizer additive component
concentration in the underlayer 902 and/or the middle layer 904
(e.g., by at least 50% by weight). In some examples, the
photoresist layer 906 has a concentration of the sensitizer
additive component 910 of about 0.1% by weight or includes
substantially no sensitizer additive component 910, while the
middle layer 904 has a concentration of the sensitizer additive
component 910 of about 5% by weight, and the underlayer 902 has a
concentration of the sensitizer additive component 910 of about 10%
by weight.
[0080] In some embodiments, the underlayer 902, the middle layer
904, and the photoresist layer 906 may have various sensitizer
additive component concentration profiles. In some embodiments, the
sensitizer additive component 910 may be substantially uniformly
distributed in the underlayer 902, the middle layer 904, and/or the
photoresist layer 906. In some embodiments, the underlayer 902, the
middle layer 904, and the photoresist layer 906 may have different
sensitizer additive component concentration profiles. In one
example, the sensitizer additive component 910 is uniformly
distributed in the underlayer 902 and/or the middle layer 904,
while the photoresist layer 906 may have a non-uniform sensitizer
additive material concentration profile (e.g., varied continuously
or varied stepwise). For example, the concentration of the
sensitizer additive component may increase with a gradient from a
top surface of the photoresist layer 906 to a bottom surface of the
photoresist layer 906. For further example, a top portion of the
photoresist layer 906 may include about less than about 0.1%
sensitizer additive component, while a bottom portion of the
photoresist layer 906 may include about 1% sensitizer additive mate
component. For further example, the non-uniform sensitizer additive
component concentration profile of the photoresist layer 906 may be
designed based on the transmittance profile of the photoresist
layer 906 to achieve uniform acid generation.
[0081] It is noted that while in the example of FIG. 14 all layers
of the patterning layer 506 include the sensitizer additive
component 910 after the doping process is performed, it is
understood that one or more of the underlayer 902, the middle layer
904, and the photoresist layer 906 of the patterning layer 506 may
include substantially no sensitizer additive component 910 after
the doping process is performed. In some examples, the photoresist
layer 906 may include substantially no sensitizer additive
component 910 after the doping process is performed.
[0082] Referring now to the example of FIGS. 4A, 4B, 4C, 4D, 15A,
15B, 15C, and 15D, illustrated are exemplary embodiments forming a
patterning layer including a sensitizer additive component at block
104 of the method 100. In such embodiments, the patterning layer
506 may include one or more sensitizer additive layers 1402
disposed between the layers of tri-layer patterning layer 506
formed by deposition or coating. This is illustrated by the
semiconductor device 15A, 15B, 15C, and 15D.
[0083] Referring now to FIGS. 4A and 15A, illustrated is an
exemplary embodiment of a method 400 forming a patterning layer 506
including sensitizer additive component 910 at block 104 of the
method 100. The method 400 starts at block 402, where a sensitizer
additive layer 1402 is formed over the substrate 502. In some
embodiments, the sensitizer additive layer 1402 may include a
sensitizer additive layer material. In some embodiments, the
sensitizer additive layer material may include an organic material.
In a further embodiment, the organic material includes a plurality
of monomers or polymers that are not cross-linked. In some
embodiments, the sensitizer additive layer material includes a
solvent. For example, the solvent may include an organic solvent
may including dimethyl sulfoxide (DMSO), tetrahydrofuran (THF),
propylene glycol methyl ether (PGME), propylene glycol methyl ether
acetate (PGMEA), n-Butyl acetate, Cyclohexanol,
.gamma.-Butyrolactone (GBL), ethanol, propanol, butynol, methanol,
ethylene, glycol, gamabutylactone, N-Methyl-2-pyrrolidone (NMP),
alkylsulfoxide, carboxylic ester, carboxylic acid, alcohol, glycol,
aldehyde, ketone, acid anhydride, lactone, halogenated alkane,
non-halogenated alkane, branched alkane, non-branched alkane,
cyclic alkane, non-cyclic alkane, saturated alkane, non-saturated
alkane, or a combination thereof.
[0084] In some embodiments, the sensitizer additive layer 1402 may
be formed by depositing a material including a mixture of a
sensitizer additive layer material and a sensitizer additive
material including the sensitizer additive component 910. The
mixture of the sensitizer additive layer material and the
sensitizer additive material may be substantially similar to the
mixture of the sensitizer additive material and the underlayer
material described above with reference to FIG. 9.
[0085] In some embodiments, the sensitizer additive layer 1402 may
include a floating additive material 1202 substantially similar to
the floating additive material 1202 described above with reference
to FIGS. 12A, 12B, 12C, and 12D. After depositing, the floating
additive material 1202 may move up to the top of the sensitive
additive layer 1402 and form a floating additive layer 1204.
[0086] The sensitizer additive layer 1402 may be formed by a
spin-on coating process, chemical vapor deposition process (CVD),
physical vapor deposition (PVD) process, and/or other suitable
deposition processes.
[0087] Referring now to FIGS. 4A and 15A, the method 400 then
proceeds to block 404, where an underlayer 902 is formed over the
sensitizer additive layer 1402. Block 404 may be substantially
similar to block 202 of the method 200. The method 400 then
proceeds to block 406, where a middle layer 904 is formed over the
under layer 902. Block 406 may be substantially similar to block
204 of the method 200. The method 400 then proceeds to block 408,
where a photoresist layer 906 is formed over the middle layer 904.
Block 408 may be substantially similar to block 206 of the method
200.
[0088] Referring now to FIGS. 4B, 4C, 4D, 15B, 15C, and 15D, in
various embodiments, the patterning layer 506 may include one or
more sensitizer additive layers disposed between or over the
underlayer 902, middle layer 904, and photoresist layer 906. The
same description provided above with reference to FIGS. 4A and 15A
regarding the underlayer 902, middle layer 904, and photoresist
layer 906 and the sensitizer additive layer 1402 applies except
with the differences noted below.
[0089] Referring now to FIGS. 4B and 15B, in an exemplary
embodiment of a method 420, at block 422, an underlayer 902 is
formed over the substrate. The method 420 proceeds to block 422,
where a middle layer is formed over the underlayer. The method 420
then proceeds to block 426, where a sensitizer additive layer 1402
is formed between the middle layer 904 and photoresist layer 906.
The method 420 proceeds to block 428, where a photoresist layer is
formed over the sensitizer additive layer 1402.
[0090] Referring now to FIGS. 4C and 15C, in an embodiment of a
method 440, at block 442, an underlayer 902 is formed over the
substrate. The method 440 proceeds to block 444, where a middle
layer 904 is formed over the underlayer 902. The method 440 then
proceeds to block 446, where a photoresist layer 906 is formed over
the middle layer 904. The method 440 then proceeds to block 448,
where a sensitizer additive layer 1402 is formed over the
photoresist layer 906.
[0091] Referring now to FIGS. 4D and 15D, in an embodiment of a
method 460, at block 462, an underlayer 902 is formed over the
substrate. The method 460 proceeds to block 464, where a middle
layer is formed over the underlayer. The method 460 then proceeds
to block 466, where a first sensitizer additive layer 1402A is
formed over the middle layer 904. The method 460 proceeds to block
468, where a photoresist layer is formed over the first sensitizer
additive layer 1402A. The method 460 then proceeds to block 470,
where a second sensitizer additive layer 1402B is formed over the
photoresist layer 906. In some embodiments, the sensitizer additive
component concentration in the second sensitizer additive layer
1402B may have a substantially greater effect on the transmittance
of the photoresist layer 906 than the sensitizer additive component
concentration in the first sensitizer additive layer 1402A. As
such, in some examples, the first sensitizer additive layer 1402A
may have a sensitizer additive component concentration higher than
the sensitizer additive component concentration of the second
sensitizer additive layer 1402B (e.g., by at least about 50% by
weight)
[0092] In various embodiments, the sensitizer additive layers 1402,
1402A, and/or 1402B may have various sensitizer additive component
concentration profiles. In some examples, the sensitizer additive
component 910 is uniformly distributed in the sensitizer additive
layers 1402, 1402A, and/or 1402B. In some examples, one or more of
the sensitizer additive layers 1402, 1402A, and/or 1402B may have a
non-uniform sensitizer additive material concentration profile
(e.g., varied continuously or varied stepwise).
[0093] Referring now to the example of FIG. 16, photo-acid
generation in the patterning layer 506 during an exposure process
is illustrated. As illustrated in FIG. 16, a photoresist layer 906
is disposed over a layer 1602. The layer 1602 may be an underlayer
902, a middle layer 904, and/or a sensitizer additive layer 1402
disposed under the photoresist layer 906. A sensitizer additive
layer 1402 is disposed over the photoresist layer 906. In some
embodiments, during the exposure process at block 106, sensitizer
additive components 910A, 910B, and 910C in various layers of the
patterning layer 506 may absorb the EUV light and generate
secondary electrons, which may be used by acid generators in the
photoresist layer 906 to generate an acid. For example, each of
sensitizer additive component 910A in the photoresist layer 906,
sensitizer additive component 910B in the sensitizer additive layer
1402, and sensitizer additive component 910C in the layer 1602 may
absorb a EUV light and generating a secondary electron. The
secondary electron's energy may be used by acid generators 1606
(e.g., a TAG, a PAG) in the photoresist layer 906 to generate an
acid.
[0094] Various advantages may be present in one or more embodiments
of the methods, devices and compositions described herein. It is
understood, however, that other embodiments may offer additional
advantages, and not all advantages are necessarily disclosed
herein, and that no particular advantage is required for all
embodiments. One advantage is that the patterning layer offers
improved lithography performance. By using a sensitizer additive
component including an element that has an absorption coefficient
of the EUV light greater than an absorption coefficient for the
main elements (e.g., carbon, oxygen, and hydrogen) in the
patterning layer, EUV light absorption is improved. Consequently,
the acid generator is more efficient in generating the acid, which
leads to better photoresist sensitivity. Another advantage is that
one or both of a floating additive layer and a topcoat layer may be
used to reduce the diffusion of the sensitizer additive component,
thereby controlling the concentration of the sensitizer additive
component in various layers of the patterning layer. Yet another
advantage is that a doping process may be used to add the
sensitizer additive component to the patterning layer, which may
help achieve various sensitizer additive concentration profiles in
the various layers of the patterning layer. Yet another advantage
is that the sensitizer additive component may include a polarity
switch protecting group and exhibit hydrophilic properties after
exposure to radiation, thereby providing for increased
hydrophilicity of exposed regions of the photoresist material.
[0095] Thus, in one embodiment described herein a method of making
a semiconductor device is provided that includes providing a
semiconductor substrate. A layer including an additive component is
formed over the semiconductor substrate. The additive component
includes a metal cation. One or more bonds bonding the metal cation
and one or more anions are formed. Each of the one or more anions
is one of a protecting group and a polymer chain bonding component.
The polymer chain bonding component is bonded to a polymer chain of
the layer. The semiconductor substrate is exposed to a radiation
beam.
[0096] In an embodiment, a method is described which includes
forming a photosensitive layer over a substrate. The photosensitive
layer includes an additive component. The additive component
includes a metal and at least one of a protecting group and a
polymer chain bonding component. The polymer chain bonding
component is bonded to a polymer chain of the photosensitive
material. The metal is bonded to the at least one of the protecting
group and the polymer chain bonding component using one or more
bonds. The photosensitive layer is selectively exposed to a
radiation beam. A developer is applied to the photosensitive layer,
which removes regions of the photosensitive layer exposed to the
radiation beam.
[0097] In an embodiment, a method of semiconductor device
fabrication is described which includes forming a first additive
layer on a target substrate. The first additive layer includes an
additive component including a metal. A photoresist layer include
an acid generator is formed adjacent to the first additive layer.
The target substrate having the first additive layer and the
photoresist layer disposed thereon is exposed using a radiation.
The additive component of the first additive layer absorbs the
radiation and generates a secondary electron. The acid generator of
the photoresist layer generates an acid using energy of the
secondary electron.
[0098] The foregoing has outlined features of several embodiments.
Those skilled in the art should appreciate that they may readily
use the present disclosure as a basis for designing or modifying
other processes and structures for carrying out the same purposes
and/or achieving the same advantages of the embodiments introduced
herein. Those skilled in the art should also realize that such
equivalent constructions do not depart from the spirit and scope of
the present disclosure, and that they may make various changes,
substitutions and alterations herein without departing from the
spirit and scope of the present disclosure.
* * * * *